A conductive coc material with electromagnetic shielding function and a preparation method thereof
By modifying carbon fibers with dopamine hydrochloride and iron oxide, a conductive COC material with electromagnetic shielding function was prepared, which solved the problem of insufficient electromagnetic shielding performance of COC materials in the prior art and achieved high conductivity and excellent electromagnetic shielding effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGXIA QINGYAN POLYMER MATERIALS CO LTD
- Filing Date
- 2022-12-29
- Publication Date
- 2026-04-10
AI Technical Summary
Existing COC materials are insufficient to meet the electromagnetic shielding performance requirements in the field of flexible circuit boards, and simply adding conductive fillers cannot effectively improve electromagnetic shielding performance.
By modifying carbon fibers with dopamine hydrochloride and iron oxide, a modified filler with magnetic iron oxide was prepared. This filler was then mixed with COC particles and carbon black and injection molded to form a conductive COC material.
It significantly improves the electrical conductivity and electromagnetic shielding performance of COC materials, meeting the application requirements of flexible circuit boards, and performs particularly well in the aerospace and military fields.
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Figure CN116355360B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of high polymer materials, and particularly relates to a conductive COC material with electromagnetic shielding function and a preparation method thereof. BACKGROUND
[0002] Cyclic olefin copolymer (COC) is a widely used thermoplastic engineering plastic. COC material has become a widely used optical material due to its extremely high transparency and low refractive index. At the same time, COC has excellent electrical properties, stable low dielectric constant and dielectric loss at millimeter and sub-millimeter wavelengths, and has a wide application space in the field of electronic communication and flexible circuit board.
[0003] In addition to the requirement of soft material, low dielectric constant (Dk) and low loss factor (Df) for the flexible circuit board material, strict requirements are also put forward for the conductive performance of the material. Even the electromagnetic shielding performance of COC material is also challenged for some flexible circuit boards applied in the field of aerospace and military.
[0004] The commonly used forming processing methods of COC material at present include press forming, extrusion forming, injection molding and calendering. Press forming refers to compacting the plastic in the room by external pressure to form a product with a specific shape and size. Extrusion forming refers to that the plastic is heated to a viscous flow state in the machine barrel and then extruded through the die by the screw. Injection molding refers to that the plastic is plasticized into a fluid under a specific high temperature environment, and then injected into the mold through the injection mold of the injection molding machine. Calendering refers to melting the plastic into a fluid under heating conditions, and then extruding the fluid through the roller.
[0005] At present, the mainstream method for improving the conductive performance of COC is to add a series of conductive fillers during the injection molding or extrusion forming process to increase the conductive performance of the COC material product. By introducing suitable conductive fillers during the processing of COC material, the conductive performance of the COC material product can be effectively improved, and the application of the material in the flexible circuit board end can be met to a certain extent. However, with the requirement of electromagnetic shielding performance of the flexible circuit board, simply blending conductive fillers cannot meet the electromagnetic shielding performance of the COC material product. SUMMARY
[0006] The present application provides a conductive COC material with electromagnetic shielding function and a preparation method thereof to improve the electromagnetic shielding performance of COC material.
[0007] In a first aspect, the present application provides a preparation method of a conductive COC material with electromagnetic shielding function, which comprises the following steps:
[0008] The carbon fiber is modified by hydrochloric acid dopamine to obtain a first modified filler;
[0009] The first modified filler is modified by ferroferric oxide to make the carbon fiber surface composite with magnetic ferroferric oxide to obtain a second modified filler;
[0010] The second modified filler, COC particles and carbon black are mixed and injection molded to obtain a conductive COC material.
[0011] As an optional implementation, the carbon fiber is modified by hydrochloric acid dopamine to obtain a first modified filler, specifically comprising:
[0012] The tris-hydroxymethyl aminomethane is prepared into a solution to obtain a tris-hydroxymethyl aminomethane solution;
[0013] The tris-hydroxymethyl aminomethane solution, copper sulfate, hydrogen peroxide and hydrochloric acid dopamine are mixed to obtain a modified solution;
[0014] The carbon fiber is immersed in the modified solution to modify the carbon fiber by hydrochloric acid dopamine to obtain a first modified filler.
[0015] As an optional implementation, the length of the carbon fiber is 1-5 mm.
[0016] As an optional implementation, the pH value of the tris-hydroxymethyl aminomethane solution is 8-9.
[0017] As an optional implementation, the mass ratio of the tris-hydroxymethyl aminomethane, copper sulfate, hydrogen peroxide and hydrochloric acid dopamine is 1:(0.05-0.1):(0.15-0.3):(0.1-0.5).
[0018] As an optional implementation, the first modified filler is modified by ferroferric oxide to make the carbon fiber surface composite with magnetic ferroferric oxide to obtain a second modified filler, specifically comprising:
[0019] The first modified filler and ferric chloride are dispersed in an ethylene glycol solution, and then mixed and reacted with polyethylene glycol and sodium acetate to modify the first modified filler by ferroferric oxide and make the carbon fiber surface composite with magnetic ferroferric oxide to obtain a second modified filler.
[0020] As an optional implementation, the reaction temperature of the mixing reaction is 180-220°C, and the reaction time of the mixing reaction is 8-24h.
[0021] As an optional implementation, the mass ratio of the first modified filler and the ferric chloride is 1:(1-8).
[0022] As an optional implementation, the mass usage relationship of the second modified filler and the COC particles satisfies: the second modified filler accounts for 1-10% of the COC particles; and / or
[0023] The mass usage relationship of the carbon black and the COC particles satisfies: the proportion of the carbon black in the COC particles is not more than 5%.
[0024] In a second aspect, the application provides a conductive COC material with electromagnetic shielding function, which is prepared by the preparation method of the conductive COC material with electromagnetic shielding function in the first aspect.
[0025] Compared with the prior art, the above technical solution provided by the embodiments of the application has the following advantages:
[0026] The method provided by the embodiments of the application introduces appropriate conductive fillers (carbon fibers, carbon black) to improve the electrical conductivity of the COC material product to meet the demand for its conductive performance; at the same time, the carbon fibers are surface-modified to be compounded with magnetic Fe3O4, and the high electromagnetic shielding capability of the magnetic Fe3O4 is used to improve the electromagnetic shielding performance of the COC material product. BRIEF DESCRIPTION OF DRAWINGS
[0027] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present application and, together with the specification, serve to explain the principles of the application.
[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.
[0029] Figure 1 The flowchart of the method provided by the embodiments of the present application. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0031] Unless otherwise specifically indicated, all materials, reagents, and equipment used in the present application are commercially available or are readily prepared by known methods.
[0032] As shown in Figure 1 The present application provides a preparation method of a conductive COC material with electromagnetic shielding function, which comprises the following steps:
[0033] S0. Pretreating carbon fibers.
[0034] In some embodiments, the length of the carbon fibers is 1-5 mm. Specifically, it can be 1 mm, 2 mm, 3 mm, 4 mm and 5 mm, preferably, the length of the carbon fibers is different, and the combination of the use amount of carbon fibers with different lengths can realize the regulation of the combination amount of magnetic magnetite on the surface of the carbon fibers. For example, 5 lengths are used in combination, and specifically, each length is 1 mm, 2 mm, 3 mm, 4 mm and 5 mm.
[0035] Specifically, in the present embodiment, a certain amount of chopped carbon fibers is added to an ethanol solution and ultrasonicated for 30 min, then washed with pure water and dried in an oven, and the length of the chopped carbon fibers is 1 mm, 2 mm, 3 mm, 4 mm and 5 mm.
[0036] S1. Modifying the carbon fibers with hydrochloric acid dopamine to obtain a first modified filler;
[0037] In some embodiments, the modification of the carbon fibers with hydrochloric acid dopamine to obtain a first modified filler specifically comprises:
[0038] S1.1. Preparing a solution of tris(hydroxymethyl)aminomethane to obtain a tris(hydroxymethyl)aminomethane solution;
[0039] In some embodiments, the pH value of the tris(hydroxymethyl)aminomethane solution is 8-9.
[0040] Specifically, in the present embodiment, 1 g of tris(hydroxymethyl)aminomethane is added to 250 ml of deionized water, and the pH value is adjusted to 8-9 to obtain a tris(hydroxymethyl)aminomethane solution.
[0041] S1.2. Mixing the tris(hydroxymethyl)aminomethane solution, copper sulfate, hydrogen peroxide and hydrochloric acid dopamine to obtain a modified solution;
[0042] In some embodiments, the mass ratio of the tris(hydroxymethyl)aminomethane, copper sulfate, hydrogen peroxide and hydrochloric acid dopamine is 1:(0.05-0.1):(0.15-0.3):(0.1-0.5).
[0043] Specifically, in this embodiment, 0.05-0.1 g of copper sulfate and 0.15-0.3 g of hydrogen peroxide are added to the trimethylol aminomethane solution, and finally 0.1-0.5 g of dopamine hydrochloride is added and stirred uniformly.
[0044] S1.3. The carbon fibers are immersed in the modified solution to modify the carbon fibers with dopamine hydrochloride to obtain a first modified filler.
[0045] Specifically, in this embodiment, the washed short carbon fibers are immersed in the above-mentioned modified solution for 1 h. Then, they are washed with pure water and anhydrous ethanol and dried to obtain a first modified filler.
[0046] S2. The first modified filler is modified with ferroferric oxide to make the carbon fibers surface composite with magnetic ferroferric oxide to obtain a second modified filler.
[0047] In some embodiments, the modification of the first modified filler with ferroferric oxide to make the carbon fibers surface composite with magnetic ferroferric oxide to obtain a second modified filler specifically comprises:
[0048] The first modified filler and ferric chloride are dispersed in a glycol solution, and then mixed with polyethylene glycol and sodium acetate for a mixed reaction to modify the first modified filler with ferroferric oxide to make the carbon fibers surface composite with magnetic ferroferric oxide to obtain a second modified filler.
[0049] In some embodiments, the reaction temperature of the mixed reaction is 180-220°C, and preferably, the reaction temperature is 200°C, and the reaction time of the mixed reaction is 8-24 h.
[0050] Specifically, in this embodiment, 2 g of dopamine hydrochloride modified short carbon fibers (i.e., first modified filler) in step 2 and an appropriate amount of ferric chloride are first added to a 200 ml glycol solution, and ultrasonic dispersion is performed at room temperature for 30 min. Then, 1.5 g of polyethylene glycol and 5.4 g of sodium acetate are added and stirred at 55°C for 1 h. Then, the mixed solution is transferred to a reaction kettle for reaction at 200°C for 8-24 h. After the reaction kettle is naturally cooled to room temperature, it is washed with pure water and anhydrous ethanol and dried to obtain ferroferric oxide / dopamine hydrochloride modified short carbon fiber material (i.e., second modified filler).
[0051] In some embodiments, the mass ratio of the first modified filler to the ferric chloride is 1:(1-8).
[0052] S3. The second modified filler, COC particles, and carbon black are mixed and injection molded to obtain a conductive COC material.
[0053] In some embodiments, the mass usage ratio of the second modified filler and the COC particles satisfies: the second modified filler accounts for 1%-10% of the COC particles; the mass usage ratio of the carbon black and the COC particles satisfies: the proportion of the carbon black in the COC particles is not more than 5%.
[0054] Specifically, in this embodiment, a certain mass of COC particles is dried in a drying temperature box at 110°C for 3 hours; the dried COC particles, a proper amount of the iron chloride / dopamine hydrochloride modified short carbon fiber material in step three and carbon black are mixed uniformly and then added to the barrel of an injection molding machine, and corresponding injection molding temperature and pressure are set, the first stage holding pressure is greater than or equal to the third stage injection pressure, and the first stage holding pressure is 25-30 Mpa; specifically, the injection molding temperature and pressure are as follows: the first stage temperature is set to 290°C, the second stage temperature is set to 290°C, the third stage temperature is set to 285°C, the fourth temperature is set to 285°C, and the fifth temperature is set to 280°C; the injection port first stage injection pressure is 40 MPa, the second stage injection pressure is 30 MPa, the third stage injection pressure is 25 MPa, the first stage holding pressure is 25-30 MPa, and the second stage holding pressure is 20 Mpa.
[0055] Based on one overall inventive concept, the application further provides a conductive COC material with electromagnetic shielding function.
[0056] The conductive COC material is prepared based on the above method, and the specific steps of the method can refer to the above embodiments. Since the conductive COC material adopts part or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, and will not be described one by one here.
[0057] The application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. The experimental methods not specified in the following examples are generally determined according to the national standards. If there is no corresponding national standard, the international standard, the conventional condition or the condition suggested by the manufacturer is used.
[0058] Example 1
[0059] A preparation method of a conductive COC material with electromagnetic shielding function, the method comprises:
[0060] Step 1: 2g of 5mm long short carbon fiber is added to ethanol solution and ultrasonic for 30min, then washed with pure water and dried in oven.
[0061] Step 2: 1 g of Tris base was added to 250 ml of deionized water, pH was adjusted to 8, then 0.05 g of copper sulfate and 0.15 g of hydrogen peroxide were added, and finally 0.2 g of dopamine hydrochloride was added and stirred uniformly. The chopped carbon fibers in step 1 were added to the above solution for 1 h of immersion. Then rinse with pure water and anhydrous ethanol and dry.
[0062] Step 3: First, 2 g of dopamine hydrochloride modified chopped carbon fibers in step 2 and 2 g of iron chloride were added to a 200 ml ethylene glycol solution and ultrasonically dispersed at room temperature for 30 min. Then 1 g of polyethylene glycol and 3.6 g of sodium acetate were added and stirred at 55°C for 1 h. Then the mixed solution was transferred to a reaction kettle and reacted at 200°C for 8 h. The reaction kettle was naturally cooled to room temperature, then rinsed with pure water and anhydrous ethanol and dried to obtain the ferroferric oxide / dopamine hydrochloride modified chopped carbon fiber material.
[0063] Step 4: First, 200 g of COC particles were dried in a drying oven at 110°C for 3 hours; the dried COC particles, 2 g of ferroferric oxide / dopamine hydrochloride modified chopped carbon fiber material in step 3 were mixed uniformly and added to the injection molding machine barrel, and the corresponding injection molding temperature and pressure were set; the injection molding temperature and pressure are as follows: the first stage temperature is set to 290°C, the second stage temperature is set to 290°C, the third stage temperature is set to 285°C, the fourth temperature is set to 285°C, and the fifth temperature is set to 280°C; The first stage injection pressure of the injection port is 40 MPa, the second stage injection pressure is 30 MPa, the third stage injection pressure is 25 MPa, the first stage holding pressure is 25 MPa, and the second stage holding pressure is 20 MPa.
[0064] Example 2
[0065] A method for preparing a conductive COC material with electromagnetic shielding function, the method comprising:
[0066] Step 1: Take 2 g of chopped carbon fibers with a length of 3 mm, add ethanol solution and ultrasonically for 30 min, then rinse with pure water and dry in an oven.
[0067] Step 2: 1 g of Tris base was added to 250 ml of deionized water, pH was adjusted to 8, then 0.1 g of copper sulfate and 0.3 g of hydrogen peroxide were added, and finally 0.2 g of dopamine hydrochloride was added and stirred uniformly. The chopped carbon fibers in step 1 were added to the above solution for 1 h of immersion. Then rinse with pure water and anhydrous ethanol and dry.
[0068] Step 3: 2g of dopamine hydrochloride modified short carbon fiber in step 2 and 2g of iron chloride were first added into 200ml of ethylene glycol solution and ultrasonically dispersed for 30min at room temperature. Then 1g of polyethylene glycol and 3.6g of sodium acetate were added and stirred for 1h under heating condition at 55℃. The mixed solution was then transferred into a reaction kettle and reacted at 200℃ for 8h. The reaction kettle was naturally cooled to room temperature, then washed with pure water and anhydrous ethanol and dried to obtain the Fe3O4 / dopamine hydrochloride modified short carbon fiber material.
[0069] Step 4: 200g of COC particles were first dried in a drying temperature box at 110℃ for 3h; the dried COC particles, 2g of iron chloride / dopamine hydrochloride modified short carbon fiber material in step 3 were mixed uniformly and added into the barrel of an injection molding machine, and the corresponding injection molding temperature and pressure were set; the injection molding temperature and pressure were as follows: the first stage temperature was set to 290℃, the second stage temperature was set to 290℃, the third stage temperature was set to 285℃, the fourth temperature was set to 285℃, and the fifth temperature was set to 280℃; the injection port first stage injection pressure was 40MPa, the second stage injection pressure was 30MPa, the third stage injection pressure was 25MPa, the first stage holding pressure was 25MPa, and the second stage holding pressure was 20Mpa.
[0070] Example 3
[0071] A method for preparing a conductive COC material with electromagnetic shielding function, the method comprising:
[0072] Step 1: 2g of short carbon fiber with a length of 3mm was added into an ethanol solution and ultrasonically dispersed for 30min, then washed with pure water and dried in an oven.
[0073] Step 2: 1g of tris(hydroxymethyl)aminomethane was added into 250ml of deionized water, the pH was adjusted to 8.5, then 0.1g of copper sulfate and 0.3g of hydrogen peroxide were added, and finally 0.4g of dopamine hydrochloride was added and stirred uniformly. The short carbon fiber in step 1 was added into the above solution and immersed for 1h. Then washed with pure water and anhydrous ethanol and dried.
[0074] Step 3: 2g of dopamine hydrochloride modified short carbon fiber in step 2 and 3g of iron chloride were first added into 200ml of ethylene glycol solution and ultrasonically dispersed for 30min at room temperature. Then 1g of polyethylene glycol and 3.6g of sodium acetate were added and stirred for 1h under heating condition at 55℃. The mixed solution was then transferred into a reaction kettle and reacted at 200℃ for 12h. The reaction kettle was naturally cooled to room temperature, then washed with pure water and anhydrous ethanol and dried to obtain the Fe3O4 / dopamine hydrochloride modified short carbon fiber material.
[0075] Step 4: 200g of COC particles were first dried in a drying oven at 110°C for 3 hours; the dried COC particles, 2g of the iron chloride / dopamine hydrochloride modified short carbon fiber material in step 3 were mixed uniformly and then added to the barrel of an injection molding machine, and the corresponding injection molding temperature and pressure were set; the injection molding temperature and pressure were as follows: the first stage temperature was set to 290°C, the second stage temperature was set to 290°C, the third stage temperature was set to 285°C, the fourth temperature was set to 285°C, and the fifth temperature was set to 280°C; the injection port first stage injection pressure was 40 MPa, the second stage injection pressure was 30 MPa, the third stage injection pressure was 25 MPa, the first stage holding pressure was 25 MPa, and the second stage holding pressure was 20 MPa.
[0076] Example 4
[0077] A method for preparing a conductive COC material with electromagnetic shielding function, the method comprising:
[0078] Step 1: 2g of 3mm long short carbon fibers were added to an ethanol solution and ultrasonicated for 30min, then washed with pure water and oven dried.
[0079] Step 2: 1g of tris(hydroxymethyl)aminomethane was added to 250ml of deionized water, the pH was adjusted to 8.5, then 0.1g of copper sulfate and 0.3g of hydrogen peroxide were added, and finally 0.4g of dopamine hydrochloride was added and stirred uniformly. The short carbon fibers in step 1 were added to the above solution and immersed for 1h. Then washed with pure water and anhydrous ethanol and dried.
[0080] Step 3: 2g of the dopamine hydrochloride modified short carbon fiber in step 2 was first added to 200ml of ethylene glycol solution and 6g of iron chloride was added, and ultrasonicated at room temperature for 30min. Then 1g of polyethylene glycol and 3.6g of sodium acetate were added and stirred at 55°C for 1h. Then the mixed solution was transferred to a reaction kettle and reacted at 200°C for 16h. The reaction kettle was naturally cooled to room temperature, then washed with pure water and anhydrous ethanol and dried to obtain the ferriferrous oxide / dopamine hydrochloride modified short carbon fiber material.
[0081] Step 4: First, 50g of COC particles are dried in a drying temperature box at 110°C for 3 hours; the dried COC particles, 2g of the iron chloride / dopamine hydrochloride modified short carbon fiber material in step 3 are mixed uniformly and then added to the injection molding machine barrel, and the corresponding injection molding temperature and pressure are set; the injection molding temperature and pressure are as follows: the first stage temperature is set to 290°C, the second stage temperature is set to 290°C, the third stage temperature is set to 285°C, the fourth temperature is set to 285°C, and the fifth temperature is set to 280°C; the injection port first stage injection pressure is 40MPa, the second stage injection pressure is 30MPa, the third stage injection pressure is 25MPa, the first stage holding pressure is 30MPa, and the second stage holding pressure is 20Mpa.
[0082] Example 5
[0083] A method for preparing a conductive COC material with electromagnetic shielding function, the method comprising:
[0084] Step 1: Take 2g of 3mm long short carbon fibers, add them to an ethanol solution and ultrasonic for 30min, then rinse with pure water and oven dry.
[0085] Step 2: Add 1g of tris(hydroxymethyl)aminomethane to 250ml of deionized water, adjust the pH to 8.5, then add 0.1g of copper sulfate and 0.3g of hydrogen peroxide, and finally add 0.4g of dopamine hydrochloride and stir uniformly. Add the short carbon fibers in step 1 to the above solution and soak for 1h. Then rinse with pure water and anhydrous ethanol and dry.
[0086] Step 3: First, add 2g of dopamine hydrochloride modified short carbon fibers in step 2 and 6g of iron chloride to 200ml of ethylene glycol solution, and ultrasonic at room temperature for 30min. Then add 1g of polyethylene glycol and 3.6g of sodium acetate and stir at 55°C for 1h. Then transfer the mixed solution to a reaction kettle and react at 200°C for 16h. Let the reaction kettle cool to room temperature naturally, then rinse with pure water and anhydrous ethanol and dry to obtain the ferric oxide / dopamine hydrochloride modified short carbon fiber material.
[0087] Step 4: 50g of COC particles were first dried in a drying temperature box at 110°C for 3 hours; the dried COC particles, 2g of the iron oxide / dopamine hydrochloride modified short carbon fiber material in step 3 and 2g of carbon black were mixed uniformly and then added to the injection molding machine barrel, and the corresponding injection molding temperature and pressure were set; the injection molding temperature and pressure were as follows: the first stage temperature was set to 290°C, the second stage temperature was set to 290°C, the third stage temperature was set to 285°C, the fourth temperature was set to 285°C, and the fifth temperature was set to 280°C; the injection port first stage injection pressure was 40MPa, the second stage injection pressure was 30MPa, the third stage injection pressure was 25MPa, the first stage holding pressure was 30MPa, and the second stage holding pressure was 20MPa.
[0088] Comparative Example 1
[0089] A method for preparing a COC material, the method comprising:
[0090] 50g of COC particles were first dried in a drying temperature box at 110°C for 3 hours; the dried COC particles, 2g of the iron oxide / dopamine hydrochloride modified short carbon fiber material in step 3 and 2g of carbon black were mixed uniformly and then added to the injection molding machine barrel, and the corresponding injection molding temperature and pressure were set; the injection molding temperature and pressure were as follows: the first stage temperature was set to 290°C, the second stage temperature was set to 290°C, the third stage temperature was set to 285°C, the fourth temperature was set to 285°C, and the fifth temperature was set to 280°C; the injection port first stage injection pressure was 40MPa, the second stage injection pressure was 30MPa, the third stage injection pressure was 25MPa, the first stage holding pressure was 30MPa, and the second stage holding pressure was 20MPa.
[0091] Comparative Example 2
[0092] The COC material was commercially available.
[0093] The COC injection materials provided in Examples 1-5 and Comparative Examples 1-2 were tested for electrical conductivity and electromagnetic shielding efficiency, and the results are shown in the following table:
[0094] Electrical conductivity / (S / cm) Electromagnetic shielding efficiency % / 10 GHz Example 1 10 -4 ]] 44％ Example 2 10 -4 ]] 45％ Example 3 10 -3 ]] 51％ Example 4 10 -2 ]] 65％ Example 5 10 -1 ]] 58％ Comparative Example 1 10 0 ]] 12％ Comparative Example 2 10 -16 ]] 1％
[0095] As shown in the above table, by using the method provided in the present application, by introducing the iron oxide / dopamine hydrochloride modified short carbon fiber material and carbon black, the electrical conductivity can reach 10 -1 , and the electromagnetic shielding efficiency can reach 58%; compared with Comparative Example 1, the electrical conductivity has slightly decreased, but the electromagnetic shielding efficiency has been significantly improved. Compared with the electrical conductivity and electromagnetic shielding efficiency of Comparative Example 2, the COC itself has been significantly improved.
[0096] Various embodiments of the application can exist in a variety of forms; it should be understood that the description of the embodiments as being in a specific form is merely for convenience and brevity and should not be construed to limit the scope of the application; therefore, the description of a specific form should be considered to have specifically disclosed all possible sub-forms and individual numbers within the range. For example, it should be considered that the description of a range from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) within the indicated range.
[0097] In this document, the positional words such as "upper" and "lower" are specifically the directions of the drawing surface in the drawings, unless otherwise stated. In addition, in the description of the specification, the terms "include", "contain", and the like mean "include but are not limited to". In this document, relational terms such as "first" and "second" and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this document, "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the cases where A exists alone, A and B exist together, and B exists alone. Where A and B can be singular or plural. In this document, "one or more" means one or more, and "multiple" means two or more. "At least one", "at least one of the following", or the like means any combination of the items, including single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can mean a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.
[0098] The above description is only a specific embodiment of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application should not be limited to the embodiments shown herein, but should be consistent with the widest scope of the principles and novel features applied herein.
Claims
1. A method for preparing a conductive COC material with electromagnetic shielding function, characterized in that, The method includes: Carbon fibers were modified with dopamine hydrochloride to obtain the first modified filler; The first modified filler is modified with iron oxide to make the surface of the carbon fiber composite with magnetic iron oxide, thus obtaining the second modified filler; The second modified filler, COC particles, and carbon black are mixed and injection molded to obtain a conductive COC material; The modification of carbon fibers with dopamine hydrochloride to obtain the first modified filler specifically includes: Tris(hydroxymethyl)aminomethane was prepared into a solution to obtain a tris(hydroxymethyl)aminomethane solution; The tris(hydroxymethyl)aminomethane solution, copper sulfate, hydrogen peroxide, and dopamine hydrochloride were mixed to obtain a modified solution; The carbon fiber is impregnated in the modification solution to modify the carbon fiber with dopamine hydrochloride to obtain the first modified filler, wherein the length of the carbon fiber is 1-5 mm. The mass ratio of the tris(hydroxymethyl)aminomethane, copper sulfate, hydrogen peroxide, and dopamine hydrochloride is 1:(0.05-0.1):(0.15-0.3):(0.1-0.5). The modification of the first modified filler with iron oxide to make the carbon fiber surface composite with magnetic iron oxide, thereby obtaining the second modified filler, specifically includes: The first modified filler and ferric chloride were dispersed in an ethylene glycol solution, and then mixed and reacted with polyethylene glycol and sodium acetate to modify the first modified filler with iron oxide and to make the carbon fiber surface composite with magnetic iron oxide, thus obtaining the second modified filler. The reaction temperature of the mixture is 180-220℃, and the reaction time is 8-24h. The mass ratio of the first modified filler to the ferric chloride is 1:(1-8); The mass ratio of the second modified filler to the COC particles satisfies the following condition: the second modified filler accounts for 1%-10% of the COC particles; The mass ratio of the carbon black to the COC particles satisfies the following condition: the carbon black accounts for no more than 5% of the COC particles. The pH value of the trihydroxymethylaminomethane solution is 8-9.
2. A conductive COC material with electromagnetic shielding function, characterized in that, The conductive COC material is prepared using the method for preparing the conductive COC material with electromagnetic shielding function as described in claim 1.